On Wed, 2011-09-21 at 12:55 +0100, Russell King - ARM Linux wrote:> Instructions such as VFP, kprobes tracing, etc are expected fault> locations, and those are fairly well controlled where they can be placed.> With things like ftrace, it certainly is the case that the unwinder can> theoretically be called from almost anywhere in a function.

Actually, kprobes can be places on any instruction in the kernel thatisn't in the section .kprobes.text.

I also strongly suspect that stack unwinding won't happen correctlyacross the boundary between the kprobes handling code and the functionwhich was probed - there's an awful lot of stack jiggery pokery going onthere.